These days information products are widely used in the society. Adapters are commonly adopted to mate all types of electronic devices to provide stable electric power. The conventional adapter includes an input end and an output end, such as one disclosed in R.O.C. patent gazette No. 529822 entitled “Power adapter equipped with a power indication light.” It is made at a size and shape to make carrying easier to be sold or carried with electronic products. It also has a power cord that can be bundled to facilitate storing. However, line retraction often is a problem on the general power adapter. To resolve the problem of line retraction R.O.C. patent No. M350899 entitled “Power adapter equipped with unit winding” proposes a structure in which a line winder (winding disc, helical spring or the like) is provided between an upper housing and a lower housing of the power adapter in addition to circuit elements to retract the conducting line. While the power adapter thus formed can keep the exterior neat and tidy, and also provide line winding function, the interior space is limited and a cooling space is needed. The line winder hinders air circulation inside and cooling power of the adapter suffers. Moreover, the adapter of a greater power contains more voluminous circuit elements and requires a larger insulation space. Hence having a built-in line winder in a large capacity adapter is not advisable.
In order to free the line winder from occupying the interior space of the adapter other techniques have been proposed. For instance, R.O.C. patent No. M299946 entitled “Concealable and extensible power adapter plug” discloses a power adapter containing a concealable and extensible plug, and also including a line winder to wind a conducting line at another end of the adapter. Although the line winder is located outside the power adapter without occupying the interior space needed for cooling and holding circuit elements, there is no holding place to hold line winder. The line winder is dangling and entangling outside the power adapter. Hence it offers no much improvement in usability than the conventional practice of carrying separated power adapter and line winder.
Moreover, most portable information products rely on the power adapter as power source. Its size and shape become important issues of portability. The commonly seen power adapter is formed in a rectangular shape. Including a line winder in the longitudinal direction of the power adapter creates a voluminous visual impression. Hence there are still rooms for improvement, especially in terms of anchoring the line winder on the power adapter and laying position.